Saturday, Sep 6, 2008
The dorsal striatum is not the only avenue into a consumer's brain. A structure right beneath it, called the nucleus accumbens, is another. Like the dorsal striatum, it is rich in the neurotransmitter dopamine, a brain chemical associated with feelings of satisfaction and reward. But unlike its upstairs partner, the nucleus accumbens is a bona fide pleasure center. It is activated by food, sex, drugs, money, victory, just about anything that feels rewarding. It helps animals to form pleasure-related mental associations and to stay motivated in the pursuit and repetition of positive experience.
The nucleus accumbens also turns out to be crucial to our taste for novelty -- which, as any marketer will avow, is a tried-and-true road to healthy (if not always healthful) sales.
"It is very deeply ingrained for us to associate potential reward with things that are new and unexpected," says Gregory Berns, an Emory University neuroscientist who studies how the brain responds to novelty. "New things grab the brain's attention by tapping directly into these reward pathways."
New information elicits activity in a neighborhood of brain structures often referred to as the limbic system, Berns says, which includes the nucleus accumbens and the striatum. Tying perceptions of novelty into the reward system makes good evolutionary sense, he explains, as it's an excellent way to keep animals attuned to changes in their environment. Nowadays, it probably also helps to make us indefatigable consumers.
"Are marketers tapping into this system unknowingly? I'd venture to say yes," says Berns. "They have this notion that they need to keep creating new things, new products, new versions of products.
"Why do people want to get new cars when their old ones work fine? It isn't just 'because it makes them happy.' A deeper explanation is that the brain is constantly seeking out new information and gets rewarded through these specific neural circuits when it finds it."
It is not only food and novelty that give an extra-hard tug on the brain's attentional resources. Just about anything a person finds especially pleasant to observe is reaching in and twisting the dopamine spigot.
One recent brain-imaging study found that the nuclei accumbentes (to use the proper plural) of young heterosexual males were activated by beautiful female faces. Plain female faces and male faces that the subjects rated as extremely good-looking had no effect. The experiment aimed to control for gender and for "pure" aesthetic judgment, and was left, it would seem, with that most marketable of blatancies, sex appeal.
Neuroscientists have made good headway in recent years figuring out why emotionally charged experiences get turned into stronger, more vivid memories than do humdrum and routine events. The key player is another limbic system structure called the amygdala. When revved up by a potent emotion -- which a good thrumming in the nucleus accumbens will generate -- the amygdala stamps the engendering event firmly into memory.
"Memories stored by the amygdala are extremely powerful," says Volkow, "because from then on, whenever you re-encounter that stimulus you will immediately associate it with the pleasure [or aversion] you first experienced."
Presumably this is one of the reasons it pays to place shapely young women on-screen mugging next to anything from flashy gizmos to fizzy sugar water. The pairing is arbitrary, but it engages a set of brain mechanisms that evolved originally to select mates, learn from serendipity, and remember intense experiences on which future survival might hinge.
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